Argentine President Cristina Kirchner dismissed a referendum that saw Falkland islanders vote overwhelmingly to remain a British territory, rejecting demands that she accept the outcome.
Kirchner, whose popularity has plummeted under economic woes at home, said the vote in the disputed South Atlantic archipelago was a "parody," and even the United States, Britain's firmest ally, acknowledged Argentina's claim.
British Prime Minister David Cameron had earlier urged the Latin American country to respect the wishes of 99.8 percent of the islanders who voted "yes" to staying a self-governing British territory, according to official results.
The islanders organized the vote in response to increasingly bellicose sovereignty rhetoric by Kirchner, and only three of the 1,517 valid ballots -- on 92 percent turnout -- were cast against the islands staying under British rule.
Kirchner's government had dismissed the referendum as meaningless and said it would not affect its claims on the Falklands, it calls them "Las Malvinas," which it failed to seize back from Britain in a brief but bloody war in 1982.
She reiterated her displeasure late Tuesday at an event at the Casa Rosada presidential mansion.
"What is important today is the United States' position about this kind of parody of a referendum," Kirchner said.
"The State Department spokeswoman said that they continue to recognize that there is a sovereignty dispute between Argentina and Britain."
The United States earlier said it took "note" of the islanders' vote, but refused once again to take sides in the dispute.
"The residents have clearly expressed their preference for a continued relationship with the United Kingdom," State Department spokeswoman Victoria Nuland said.
"That said, we obviously recognize that there are competing claims."
The announcement of the result overnight Monday sparked jubilation in the islands' tiny capital Stanley, and Cameron said he was "over the moon" at the outcome.
"The Falkland Islanders couldn't have spoken more clearly. They want to remain British and that view should be respected by everybody, including by Argentina," he said.
Cameron, who later telephoned the chairman of the islands' legislative assembly to congratulate him on the result, also warned against any military action by Argentina.
"People should know we will always be there to defend them," he said.
Barry Elsby, a member of the legislative assembly, told AFP from Stanley as the numbers came in that the result "sends a message around the world."
"There are hundreds of people outside the cathedral, celebrating, singing and waving flags."
International observers from Canada, Chile, Mexico, New Zealand, Paraguay, the United States and Uruguay monitored the referendum on Sunday and Monday and declared it "free and fair."
However, Alicia Castro, Argentina's ambassador to London, said the referendum was a "ploy" to detract from the "weakness" of Britain's claims.
"It's a very predictable result, because the current inhabitants of the Malvinas are British. But the territory in which they live is not," she said.
The referendum had sparked huge enthusiasm among the Falkland Islands' 2,563 permanent residents, four-fifths of whom live in Stanley, with its typically British pubs and red telephone boxes.
The remaining several hundred islanders are scattered in isolated sheep farms and tiny settlements.
London has held the Falklands since 1833 but Buenos Aires says this is an occupation and the British residents are colonial implants with no right to self-determination.
It says the United Nations had issued 40 resolutions calling on Buenos Aires and London to negotiate over sovereignty.
Tensions between the two sides have increased in recent years against a backdrop of the discovery of oil reserves in the waters off the Falklands, the 30th anniversary of the 1982 war and domestic political difficulties facing both governments.